PROJECT HIGHLIGHT
This study quantifies the movement of microplastics within the Monterey Bay watershed and determines the major local sources of microplastic pollution, filling a geographical gap in research between the San Francisco Bay and Southern California Bight region.
PROJECT SUMMARY
This project is quantifying microplastic flux into and within Monterey Bay, a large, biologically rich, open ocean bay in central California — and a site where, compared to other portions of the California coastline, data has been historically lacking. The research team is combining optical microscopy and spectroscopy to track how these plastics move from land to sea and into marine animals.
The team is collecting and analyzing materials throughout the watershed and marine ecosystem. To date, it has gathered 40 beach samples near river mouths, 8 ocean water samples from offshore waters and 73 river samples from sites on the Salinas, Pajaro, San Lorenzo and Carmel rivers just upstream of estuarine influence. Working with partners, the team has also collected samples of krill, forage fish and baleen whale fecal material to trace microplastics through marine food webs.
Laboratory analysis has revealed thousands of microplastics in the samples, ranging from micron-scale to several millimeters in size. Most are fibers. Using a combination of optical microscopy and spectroscopy in a weight-of-evidence approach, researchers have identified polyolefins as the most numerous plastic type in analyzed samples. While parent materials cannot be definitively determined, polyolefins are commonly used in food packaging, which is a frequent macro-litter item found during local beach cleanups. Community engagement has been an integral part of the project, with 60 volunteers ranging from high school and college students to emeritus professors and retirees participating in fieldwork activities. The project is a partnership that includes collaborators from government, academia, NGOs and industry, and will provide detailed recommendations to the Regional Water Quality Control Board regarding site-specific best management practices to mitigate microplastic inputs into the Monterey Bay National Marine Sanctuary.
Matthew Savoca